Fluid-pressure brake



Aug. v18, 1925. V 1,549,782

J. C. MCCUNE FLUID PRESSURE'BRKE Filed Sept. 30, 1924 ,as iii? IlIIll-lllllllhl u INVENTO JOSEPH QMCCUNE ATTORNEY "To alloro/Troni, t muy concern p l useful improvements ,y Brakes, oi which the following is a specilica- JOSEPH C. WICCUNE, OF SOUTH. ORANGE,

Y U81?. A1B. ERMSE F PENNSYLVANA.

Laissez e reni" ortica.

ELU 11B-PRESSURE BRAKE.

application led September Beit lrnoivn thatv l, Joeri-"rt C. lvleCnNn, a citizdn oi the United Stateaf ,residing Vat South Grange, in the'county el lsseirand State olilleiv Jersey, .have inventednevs and in Fluid-Pressure tion.

Vlhis invention relates te fluid pressure brakes, and more particularly to a brake 'equipment in which a limiting, valve device is employed to liiiiit the maximum kdegree ot pressure of luid supplied to the brake cylinder in applying the brakes, such as is the case in the equipment disclosed in prior Patent No. 1,285,001 ol Walter lvl. rlurner, dated May 7, 1918.

l/Vhere a maximum pressure limiting valve device is employed, there is some possibility that the limiting valve may fail and the principal object oi my invention is to provide means itor ensuring that a certain bralre cylinder pressure Will be obtained in the event that the limiting valve device should tail.

ln the accompanying drawing, the single ligure is a sectional View of a portion ot a liuid pressure brake apparatus, showing my improvement applied thereto.

n order to illustrate one application of my invention, l have shown in the drawing the service pressure limiting valve portion as disclosed in the hereinbetore mentioned Patent No. 1,265,001, comprising a valve piston 121n `or controlling communication Ylroim passage 128, through which Jfluid under pressure is supplied in applying the brakes, to a passage 129 which leads to brake cylinder pipe 8. il. valve 132 controls communication from the spring chamber ot the valve piston 127, by Way ot passage 183, to brake cylinder passage 128, and said valve is controlled by a diaphragm 180, subject on one side to the pressure oi an adjustable regulating spring 181.

When an application of the brakes is made, tluidsupplied by operation of the usual triple valve device flows to pipe 18 and thence through iassage 128 to the Jlace oi valve piston 121, causing said valve piston to move trom its seat, so that communication is opened 'from passage 128 to passage 129. Fluid under pressure is then sup- 30, 192% Serial No. 240,759.

pressure or springll, the diaphragm Will be operated to permit the valve 132 to seat..

r1`liis alloivstlie fluid pressures to equalize on opposite sides ot the vvalve pistons, permitting the spring 186 to move the valve pis-` ton to its seat, thus cutting oil` the `further flow of fluid to the brake cylinder.

According to my invention, to ensure that liuid under pressure .vill be supplied to the brake cylinder in the eventthat the valve 182 should tail, a ley-pass connection roinf the supply pipe 18 to the brake cylinder pipe 8 is provided. ln said by-pass connection a valve device is interposed comprising a casing 1 having avalve chamber 2 containing a valve 8 for controlling communication trom pipe 18 to pipe 8. For controlling the operation oit valve 3, a piston t is provided, Which is subject on one side to the pressure of tiuid supplied to the brake cylinder and on the other side to the pressure ot a coil spring 5, which is such that a predetermined minimum bralre cylinder pressure,

acting on the opposite side of the piston, ,Will overcome the pressure oi the spring.

ln operation of my improvement, when fluid under pressure is supplied to pipe 18 in applying the brakes, fluid will flow 'from pipe 18 past the valve 8 to pipe 8 as Well as to passage 128 and the pressure limiting valve device. YWhen the bra-ke cylinder sressure has been increased to the minimum pressure :tor which the spring 5 is adjusted, the piston d- Will be operated so as to permit the valve 8 to seat and thus cut ed the turther lovf ot fluid to the brake cylinder, as

supplied through the by-pass connection.`

rElie limiting valve device will then act in the usual manner to limit the maximum pressure of i'luid which may be supplied to the brake cylinder.

lt Will thus be evident that should the pressure limit-ing valve device fail to permit the supply ot iiuid to the brake cylinder, fluid under pressure will still be supplied to the brake cylinder, by Way ot the by-pass connection until the bralre cylinder pressure has been increased to the vminimum predetermined pressure tor Which the by-pass valve device is adjusted.

and when the pressure of liuid supplied, act-` ing on diaphragm 180, slightly exceeds the Having` now described my invention7 what I claim as new and desire to secure by Letters Patent, is

l. In a iuid pressure brake, the combination With a brake cylinder and a limiting valve device for limiting the maximum degree of pressure of fluid supplied to the brake cylinder, of a valve device for controlling` a normally open by-pass connection through which fiuid is supplied to the brake cylinder.

2. In a fluid pressure brake, the combination With a brake cylinder and a limiting valve device for limiting the maximum degrec of pressure of fiuid supplied to the brake cylinder, of a normally open by-pass connection through Which fiuid is suoplied to the brake cylinder and a valve device for controlling communication through said bypass connection.

3. In a fluid pressure brake, the combination With a brake cylinder and a limiting valve device for limitingthe maximum degree of pressure of fiuid supplied to the brake cylinder, of a valve for controlling a normally open by-pass connection through which fluid is supplied to the brake cylinder and a piston subject to the pressure of fiuid supplied to the brake cylinder for controlling the operation of said valve.

4. In a fluid pressure brake7 the combination with a brake cylinder and a limiting valve device for limiting the maximum degree of pressure of fluid supplied to the brake cylinder, of al valve for controlling a normally open by-pass connection through -vhich fluid is supplied to the brake cylinder and a piston subject to the opposing pressures of the brake cylinder and a spring for `controlling` the operation of said valve.

5. In a Huid pressure brake, the combination with a brake cylinder and a limiting` valve device for limiting` the maximum degree of pressure of iiuid supplied to the brakecylinder7 of a. valve for controlling a by-pass connection through which fluid is supplied to the brake cylinder and a piston subject to the opposing pressures of the brake cylinder and a spring and Operated upon a predetermined increase in brake cylinder pressure for permitting said valve to close.

In testimony whereof I have hereunto set my hand.

JOSEPH C. MCCUNE. 

